It is known that antimicrobial hand sanitizers containing a high concentration of alcohol are effective in killing microorganisms when used by routinely washing one's hands with the sanitizer. Although alcohol-containing sanitizers are known to possess good antimicrobial activity and prevent infections, such sanitizers typically require the use of a minimum of from 60% of an alcohol such as ethanol to be effective. However, use of alcohol on the skin at these concentrations often severely dries the skin as the alcohol dissolves the sebum from the skin. Consequently, continuous use of such products can leave the user's skin dry, often resulting in red, chapped, and cracked skin.
To prevent a user's skin from drying due to use of a high alcohol content sanitizer, many such products include moisturizers, for example, humectants and emollients, as additional components in their formulations. While providing some protection against drying of the skin, there are disadvantages to the use of these sanitizers due to the addition of the moisturizers. For example, conventional sanitizers containing moisturizers or other hydrophobic skin protectants are unstable and tend to break down over time. As a result, the added moisturizers or skin protectants do not remain distributed throughout the sanitizer whereby the moisturizing ability of the sanitizer becomes ineffective. Additionally, the instability of the sanitizers may cause the formation of large oil layers on the skin and, as a result, the sanitizer may feel greasy and not aesthetically pleasing when applied to the skin.
The adverse effects on the skin resulting from the use of sanitizers containing a high concentration of alcohol are more fully described in U.S. Pat. No. 7,683,018 and in U.S. Patent Publication Number 2009/0226498. These publications also describe the difficulties encountered when moisturizers or other hydrophobic skin protectants are added to such compositions.
The invention of U.S. Pat. No. 7,683,018 is described as an antimicrobial high alcohol content composition in the form of a gel or foam. It is stated that compositions that foam when dispensed from a suitable dispenser are stable and do not require the use of propellants and pressurized containers. The gels are described as having a viscosity of less than 4,000 cps as they specifically exclude gelling or thickening agents of the type typically found in commercial gels and creams. According to the disclosure of said patent, after single or multiple applications of the gel, there is no tacky or sticky after-feel and the gel does not clog the dispensers from which the gels are dispensed. To the extent that this is so, it is believed that the absence of gelling or thickening agents and the control of composition viscosity may contribute to the absence of a tacky feel. However, it is also believed that the absence of gelling or thickening agents from the formulations result in reduced consumer appeal.
The invention of U.S. Patent Publication Number 2009/0226498 relates to antimicrobial hand sanitizers that include alcohols and a high internal phase emulsion. The internal phase emulsion is stated to permit moisturizers or skin protectants, such as emollients and/or silicones, to be stably incorporated into the sanitizer. The internal phase emulsion has an aqueous phase in an amount of about 30% (by weight of the emulsion) or less. It is stated that due to the use of the internal emulsion phase, the sanitizer has antimicrobial efficacy and a good moisturizing effect. It is further stated that by incorporating the moisturizer or skin protectant into the alcohol-based hand sanitizer as part of a high internal phase emulsion, the moisturizer or skin protectant remains substantially uniformly distributed throughout the sanitizer for extended periods of time and does not separate out as a separate phase. It is speculated in the application that the reason for this stability is that the emulsion has a mean droplet size of about 5 microns or less allowing droplets to remain suspended throughout the sanitizer for the extended period of time. To formulate the sanitizer, it is necessary to prepare the emulsion separately from the remaining components of the sanitizer. Methods used to prepare the emulsions include the use of high pressure/high shear mixing conditions. Following preparation of the emulsion, it is combined with the other sanitizer components at room temperature by mixing. Disadvantages that might be associated with the sanitizer of the referenced application include the high cost of manufacture and the possibility of instability due to breaking of the emulsion over prolonged time, especially during storage and shipment in adverse weather conditions.
The invention described herein is a high alcohol content antimicrobial gel or cream that contains moisturizing components as well as thickening or gelling agents. When used, the sanitizer destroys bacteria; moisturizes the skin thereby avoiding red, chapped, and cracked skin; and does not leave an oily residue and a tacky feel on the skin. It is believed that these advantages result from the addition of certain phospholipids to the composition in controlled concentration.
The use of phospholipids in skin cream formulations is known and plays a significant role in the cosmetics and pharmaceutical industries because of their stated outstanding physiological properties, such as, for example, emulsifying, softening, and anti-oxidant effects.
U.S. Pat. Nos. 6,440,456 and 6,524,614 disclose the use of phospholipids in delivery compositions for the purposes of solubilizing insoluble components into the composition. Amongst the cosmetic products described in this patent improved by the addition of phospholipids are shampoos, conditioners, deep treatments for hair, body washes, bath gels, hair dyeing compositions, permanent wave formulations, relaxers, make-up preparations, particularly mascara and foundation, and skin creams or lotions. The majority of the working examples within the patent are directed to hair treatment compositions.
In Chinese Patent No. 101381656 (A) (Method for Preparing Soya Bean Lecithin Hand Cleanser) having a publication date of Mar. 11, 2009, a soybean phospholipid hand sanitizer is disclosed. The sanitizer is said to be a foam, but does not contain an alcohol. The soybean phospholipid used is a mixture of phospholipids comprising cationic and non-ionic phospholipids in addition to anionic phospholipids. The total concentration of the phospholipid in the sanitizer is from 0.4 to 0.5% by weight of the formulation.
U.S. Pat. No. 4,464,400 is directed to a skin care base material for external use where the invention is said to be the use of a phospholipid in combination with an ester of a fatty acid and a polyoxyethylene fatty acid ester. In accordance with the patent, it was found that a skin care base material for external use having adequate stability and providing a “good feel” when applied to the skin is obtained by combining a phospholipid with the ester of a fatty acid and the ester of a polyoxyethylene fatty acid. It is stated that the preferred amount of the phospholipid may range between 0.10 to 20% by weight, preferably from 0.2 to 6% by weight, based upon the weight of the entire composition. Phospholipids disclosed include non ionics, anionics and cationics. The patent also discloses that various other components may be incorporated into the formulation to obtain an aqueous mixture, such as a solution, a colloidal solution, an emulsified lotion, a hydrophilic cream or an aqueous gel, where the aqueous phase constitutes a continuous phase, or an oil mixture such as a water in oil cream or solution. Disclosed components include those commonly used for cosmetics or medicines for external use, such as an oil-and-fat component, an emulsifier, a dispersant, a gelating agent, a chelating agent, a perfume, a vitamin, an anti-inflammatory agent and a moisture maintaining agent such as urea.
Skin cream compositions containing anionic phospholipids are disclosed in U.S. Pat. Nos. 5,738,856 and 5,581,543, each incorporated herein by reference. The invention of said patents is described as a topical treatment composition for skin disorders. It comprises a compound in a pharmaceutically acceptable carrier for topical delivery to the skin that penetrates the epithelial surface to provide prolonged lubrication and moistening. The invention is said to be based upon the discovery that in order to provide prolonged lubrication and moistening of the skin, it is desirable to replicate and replenish the bilayer lamellae naturally occurring in healthy skin. To accomplish this, a formulation is disclosed that is a pharmaceutically acceptable topical carrier containing a compound having one or more polar terminus groups and one or more non-polar terminus groups where the polar and non-polar groups are separated from each other by a spacer segment, referred to in the patents as a bilayer component. Suitable bilayer components disclosed are phospholipids and triglycerides. Negatively charged phospholipids—i.e., anionic phospholipids, are said to be a preferred bilayer component.
Promotional materials for commercial products also identify the use of phospholipids in cosmetic compositions. For example, in a promotional publication entitled “Sanitizing—Hand Sanitizer Moisturizer”, [available at website HTTP://www.goldbondultimate.com/hand-sanitizer-moisturizer.html] used in connection with the sale of a commercially available hand sanitizer moisturizer sold under the Trade Name “Gold Bond Ultimate”, it is stated that the formulation contains a “Phospholipid Complex that helps restore your skin's lipid layer.” Similarly, a product identified as Purell Instant Hand Sanitizer with a Touch of a Lubriderm Moisturizer (uses: for hand washing to decrease bacteria on the skin, recommended for repeated use) identifies a phospholipid as one of its components. The label on its container identifies U.S. Pat. Nos. 5,302,377 and 5,652,274 as patents relating to the product.
Notwithstanding the frequent use of phospholipids in cosmetic compositions as disclosed in the above publications, none of the above publications disclose a formulation having a phospholipid in a product having a high alcohol concentration suitable for use as a hand sanitizer.